* { box-sizing: border-box; }
    html, body {
      margin: 0;
      padding: 0;
      height: 100vh;
      background: #2b2b2b;
      color: #e0e0e0;
      font-family: 'Courier Prime', monospace;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .card {
      position: relative;
      background: #1e1e1e;
      border: 2px solid #3a3a3a;
      border-radius: 8px;
      padding: 2rem;
      width: 460px;
      box-shadow: 0 0 10px rgba(0,0,0,0.8);
    }
    h1 {
      margin-top: 0;
      font-size: 1.4rem;
      text-align: center;
      border-bottom: 1px solid #3a3a3a;
      padding-bottom: 0.5rem;
    }
    .section {
      margin: 1rem 0;
      font-size: 0.9rem;
      line-height: 1.5;
    }
    .section strong {
      color: #00ff88;
    }
    .hash {
      display: block;
      margin: 0.5rem 0;
      padding: 0.5rem;
      background: #2b2b2b;
      border: 1px dashed #505050;
      font-family: monospace;
      word-break: break-all;
      color: #ffcc00;
    }
    .input-group {
      display: flex;
      flex-direction: column;
      margin-top: 1.5rem;
    }
    .input-group input {
      padding: 0.6rem;
      font-size: 1rem;
      border: 1px solid #3a3a3a;
      border-radius: 4px;
      background: #2b2b2b;
      color: #e0e0e0;
    }
    .input-group button {
      margin-top: 0.8rem;
      padding: 0.6rem;
      font-size: 1rem;
      background: #3a3a3a;
      border: none;
      border-radius: 4px;
      color: #e0e0e0;
      cursor: pointer;
    }
    .input-group button:hover {
      background: #505050;
    }
    #result {
      margin-top: 1rem;
      text-align: center;
      font-family: monospace;
      font-size: 1rem;
    }